World Bank President Jim Yong Kim unexpectedly resigned Monday, more than three years before the end of his term, handing Donald Trump significant control over the leadership of the institution that is due to lend $80 billion this year.

Kim was first named to the post by then-president Barack Obama in 2012, when Kim was president of Dartmouth College, and reappointed at the end of his presidency for a term ending in 2022. In a letter to staff, Kim said he was leaving to join a firm to “focus on increasing infrastructure investment in development countries” but provided no additional details.

“The opportunity to join the private sector was unexpected, but this is the path through which I will be able to make the largest impact on global issues like climate change and the infrastructure deficit in emerging markets,” he wrote.

The World Bank presidency is the most senior leadership post of a multilateral institution to open since Donald Trump became president in 2017. The spot has historically been controlled by the United States, which is the World Bank Group’s largest shareholder.

A physician and anthropologist by training, Kim’s career focused on public health before he was named to the World Bank.

The bank went through a historic and controversial process during Kim’s tenure for rules requiring consideration of human rights and environmental factors in lending, during which he was accused of retaliating against an LGBT employee leader. But his tenure was marked by the first major discussion of considering LGBT rights, and the bank took the unprecedented step of freezing a major loan to Uganda in 2014 in response to the country’s adoption of a sweeping anti-LGBT law that year.